The present invention relates to a latent Lewis acid catalyst suitable for use in a storage-stable, one-part, curable resin system.
Storage-stable, one-part, curable resin systems generally comprise two or more reactive or reaction-producing components stored in an intimately admixed, unreactive state which, ideally, react rapidly when subjected to a suitable stimulus, such as application of heat or mechanical shear. Such systems, combining a cationically curable resin and a latent Lewis acid catalyst, would be of considerable value (since two-part systems of these constituents cure rapidly to form strong bonds and have other properties which are valuable in particular uses, e.g. in some cases curing without the release of volatiles). Various attempts have indeed been made to prepare one-part systems from these and similar constituents, for example by adsorbing the catalyst into a carrier, by encapsulating or otherwise shielding it from the curable resins until released by the action of heat or pressure, etc. However these attempts (of which British Pat. No. 1,103,202, British Pat. No. 1,158,662 and U.S. Pat. No. 3,018,258 are illustrative) have met with only limited success due largely to difficulties in combining suitable stability prior to activation, speed of reaction after activation and overall adhesive properties.